forkId - event and variable declaration does not fit together

[josojo]

The forkId is declared as immutable:
https://github.com/0xPolygonHermez/zkevm-contracts/blob/main/contracts/PolygonZkEVM.sol#L163

But at the same time, we have an event for updates of the forkId.
https://github.com/0xPolygonHermez/zkevm-contracts/blob/main/contracts/PolygonZkEVM.sol#L365

That does not make sense unless you intend to overwrite it with "parent contracts".

[invocamanman]

Hey! this variable indicates the version of the prover (zkROM/executor). So this can only be updated when we upgrade, the contracts
This event is useful tho, because when we upgrade the system adding new features, the synchronizer of our network will be able to know which version of the prover have to use for every batch,